bassett



T. D. BASSETT, OF GH-ARLESTOWN, MASSACHUSETTS.

Letters Patent No. 79,721, dated July?, 1868.

vIIVIPROVFIhllli'Nl' IN LATHES FOR SCREW-CUTTING.

@Le Segnale rentrer n in tigen httttt rztin ma nutten @nrt nf; tte-timo. *v TO ALL WHOM IT MAY CONCERN2- Beit known that I, T. BASSETT, of Charlestown, in the county of Middlesex, and State of Massachusetts, have invented certain new and' useful Improvements in Screw-Cutting Lathes; and I 'do hereby declare that the following, taken in Vconnection with the drawings which accompany and form part of this specieation, is a description of my invention sufficient to enable those skilled in the art lto practise it.

This 'invention consists in the combination of ajointed shaft with a rotating' burr-cutter, mounted on a swinging frame; also, in combining these last-named features with a weighted and sliding tool-rest; also, in arranging the dead-centre inthe edge of the tail-stock, for the'purpose hereinafter described.

Figure l'shows a front elevation of` a screw-cutting lathe embodying my invention.

Figure 2 shows the same in plan, and

Figure 8 a cross-section and an elevation of the parts beyond, the section being taken on the line z z, seen in iigs. l and 2, the elevationbeing ot' the parts seen looking toward the tail-stocl:.

fa is the lathebcd; b, the head-stock; c, the tail-stock; d, the slide-carriage, having a transverse motion imparted to it along the blanl; in any well-known manner, and which carries the burncutter e. This cutter is mountcdon' an arbor, which has its bearings in a piece,f, which isjmade so thatit can pivot or swing and be secured in any ordinary manner needed to give the proper inclination of thc cutter to correspond with the angle of the pitch of the screw-threads to be cut.

To the end of the arbor g, carrying the burr-cutterc, a splined shaft, 17e, is coupled by means of a universal joint at z', said shaft being supported in bearings in a piece, j, vwhich is capable of yielding to the amount required by the'movements and position of the cutter-arbor.

Between the bearings of piece j there is a cone-pulley, le, fixed to the shaft-7L, by means of a feather, so that by means of a belt on the pulley the shaft L can be rotated,'and will be free to' slide through tire pulley.

The carriage, to which the pieeefis attached, is a compound one, there being in the piece-cl a piece, d', which is capable of moving in rZ crosswise with'respect to the centre of the piece which is to be turned. This crosswisc movement isgiven asfollows: Parallel with the lathe-centres there is mounted, in suitable bearings, a mandrel, @which is geared from the lathe-mandrel m, so as to rotate isochronously therewith, and on this xnandrelZ is fixed a pattern-cam, n, o f any'desired length and form of cross-section. Against this patterncam a projection, o, from the piece d is kept in Contact by means of a weighnf), or spring, suitably arranged for that purpose, so that it will be obvious that as the pattern-cam n is made to rotate, the eutt'er e will be drawn toward and will be forced from the centre oi the screw g, by the conjoined action of the cam n and weight p acting through the cross-slided, this movement being that which is required in the formation of screw-taps with several faces. A

By disconnecting from the lathe the piecesfandj, with their immediate connections, and by removing the partei-acum and weighty-the lathe may be used as an ordinary one for turning plain cylindrical bodies with an ordinary tool, there being a tool-post, r, provided, in which to 'secure the tool, or Vkeeping the weight and providing a pattern-cam, fac-similcs of' the pattern-cam may be turned in the la the with an ordinary cutting-tool or point.

Inspection of 3 will show how thc tail-stock c is offset or set` back, so as to bring the dead-centre s to the'ront, and thus alford room for the passage of the universal joint, seenV at z', and the bearings of the man- .drol g to allow theburr-cutter e to operate on the extreme end of a piece mounted on the lathe-centres.

I do not claim the devices, separately considered, herein described, but Y 1. The combination of the jointed shaft it, burr-cutter e, and its swinging framef.

2. The combination of the elements last above mentioned with the weighted and sliding tool-rest.

3. Arranging the dead-centre in the edge of the tail-stock in the manner and for the purpose described.

T. D. BASSETT.

Witnesses:

Criss. ROBINSON, Jr., L. H. LATIMER. 

